Core Routing Module. Ladislav Lhotka 29 March draft-lhotka-netmod-routing-cfg-00

Transcription

1 Core Routing Module draft-lhotka-netmod-routing-cfg-00 Ladislav Lhotka 29 March 2011

2 Objectives e data model should be suitable for the common address families, in particular IPv4 and IPv6, unicast and multicast. Simple routing setups, such as static routing, should be configurable in a simple way, ideally without the need to write additional YANG modules. e framework must allow for complicated setups including multiple routing tables and multiple routing protocols, and controlled redistribution of routing information. Vendors should be able to map data models using this framework to their proprietary data models and configuration interfaces. 2

3 Block Diagram kernel FIB F F static routes F main routing table F F additional routing table F F F F routing protocol routing protocol 3

4 Framework Components route routing table routing protocol instance route pipe route filter 4

5 Route Routes are used in both configuration data (static routes) and operational state data (routing tables). Minimal content model, open to enhancements. route-type "unicast" (default), "multicast" and "unicast" destination-prefix next-hop outgoing-interface 5

6 Routing Table Operational state data, a list of routes bundled with administrative data: source-protocol, last-modified date and time of last modification or creation. New RPC operation, delete-route, is used for deleting a route from a specified routing table. Every compliant implementation MUST automatically configure the main routing table. Additional routing tables may be configured, each identified by a unique name. Questions: 1. Should the name of the main routing table be fixed? 2. Should the (main) kernel routing table also be mandatory? 6

7 Routing Protocol Instance Any number of routing protocol instance may be configured, each is identified by a unique name. Each routing protocol instance MUST be connected to a routing table, by default it is the main routing table. Two route filters control the exchange of routes import-filter (protocol table) and export-filter (table protocol). e module defines two pseudo-protocols: "direct" (exactly one instance) and "static". 7

8 Defining New Routing Protocols New identity MUST be defined for each protocol type, e.g. identity rip { base rt:routing-protocol; description "Identity for the RIP routing protocol."; } New route attributes MAY be defined. e routing-protocol-instance container MAY be augmented with protocol-specific configuration data, e.g. augment "/rt:routing/rt:routing-protocol-instances/" + "rt:routing-protocol-instance" { container rip-configuration { when "../rt:type='rip'";... } } 8

9 Route Pipe A unidirectional link connecting two routing tables. Each route pipe is identified by a unique name. e transport of routes is controlled by means of a route filter. Route pipes are defined out of band : <route-pipe> <name>...</name> <origin>...</origin> <recipient>...</recipient> <route-filter>...</route-filter> </route-pipe> 9

10 Route Filter Route filter may be defined to allow or deny selected routes, but also to manipulate them. Each route filter is identified by a unique name. e module defines no route filtering language, this is expected to be done in other modules (and by another WG?). erefore, the only two configurable policies are allow all and deny all. 10

11 Potential YANG Deficiencies 1. Lack of support for YANG data types in XPath expressions leafref, instance-identifier, identityref, perhaps a few important derived types such as IP addresses. leaf location { type string; when "derived_from(../type, 'physical-interface')"; } 2. Requirement on uniqueness of leaf-list entries how to model AS PATH? 3. In order to create leafref links from module A to data nodes appearing in module B, module A has to import module B. But imports cannot be circular, so what if a link from B to A is also needed? Solution: A and B are one module (see the IPFIX data model). A more flexible mechanism for addressing nodes in other modules is needed, circularity has to be avoided only when importing definitions. 11